Windows are typically provided with screens fitted to the inside of the frame of the window opening, typically fixed to the upper face of the window opening or between the sides of the window opening adjacent the upper face thereof, for selectively obscuring the window. In the case of a roller blind, a roller is mounted at an upper side of the frame around which a suitable screen is wound. The screen may be lowered and raised by rotating the roller. The lower end of the screen may be provided with a bar such that the screen hangs from the roller under gravity. The roller, upon which the screen is wound in convolute manner, is typically located within an elongate cassette adapted to be mounted at an upper side of a window opening.
Over time the screen of a roller blind assembly may become dirty, faded or damaged or it may be desired simply to change the screen, for example when a room is redecorated. This usually requires costly replacement of the entire roller blind assembly.